Avalanche forecast

Northwest Mountains

Crested Butte Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

Recent snowfall and west to northwest winds have created fresh drifts on leeward terrain at upper elevations.  It is possible for you to trigger an avalanche in areas with signs of recent drifting.  Areas beneath ridgelines, below cornices, and cross-loaded features are the most suspect locations.  Take the time to identify slopes with recently formed drifts and either make a thoughtful assessment or steer away from them to areas sheltered from the wind.  

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Fresh snow and moderate winds initially from the west and now from the north have combined to create a wind slab avalanche problem. These slabs are expected to average 6 to 12+ inches thick and have formed on a variety of weak old snow surfaces. Remotely triggering this avalanche problem is a possibility as you approach wind-loaded terrain features. Plan ahead and use caution around terrain features like the lee sides of ridgelines and cross-loaded gulleys for example. This avalanche problem will be more common and problematic above treeline. At near treeline elevations, these slabs will not completely disappear but be more isolated in their distribution. 

    Example of a shallow wind slab on the lee side of a ridgeline. 

Avalanche Discussion

The current avalanche hazard is being driven by the recent snowfall from Wednesday.  Storm totals range from 2 to 7 inches with a chance that some areas in the Ruby Range (the Northwest Mountains forecast area) are even a bit deeper than 7 inches.  Snowfall data from the Southeast Mountains is a bit more sparse but totals are likely less than in the Northwest Mountains.  Along with the new snowfall came moderate winds from westerly directions which have now shifted to the north.  An observation from yesterday, in an interior part of the range, found surprisingly little evidence for wind drifted snow even at ridgetop, but with relatively poor visibility the evidence may have simply been out of view.

While you are traveling through the mountains today look for signs of recent drifting.  These include stiffer snow surfaces, texture in the snow, slopes immediately adjacent to scoured areas, or terrain below cornices with fresh growth.  Shooting cracks in the snow are also a clear sign of instability  If you identify these characteristics you can simply avoid those slopes, or make a thorough assessment before committing to upper elevation terrain with evidence of wind effect.  Keep in mind that the wind has swapped directions and loading patterns may have changed over the course of the storm.  

A smaller concern for today will be Dry Loose Avalanches in sheltered areas on the north half of the compass.  The storm snow fell on a very weak snowpack, particularly on sheltered northerly slopes.  Dry Loose avalanches are expected to remain relatively small, but you could still take a small ride and hit rocks or stumps.

 

 

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